Re: Low redisplay performance (23 regression)

So, the slowdown may be related to displaying multiple faces? I have
not experienced anything like this, myself. If you do M-x

list-faces-display and scroll through that buffer, is there a
slowdown?

Yes, definitely, but if and only if face-remapping-alist is enabled
(remapping the default face).
With the tabbar enabled, scrolling down that buffer takes about twice
as long, depending on how many tabs I show.

Without the tabbar, I estimate the slowdown is about 20-30%.

It's possible that tabbar is doing something with its face computation
that is much more expensive on Emacs 23 than on Emacs 22; I don't have
time to look at its code, however.

As above, it's not just the tabbar; doing something relatively simple
with face-remapping-alist already shows the effect.

I've been working on coming up with a reproducible standalone
example. Perhaps, if the others who can reproduce, could attempt the
same, we'd get somewhere.